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How to take A7 core to Deep Sleep Mode while keeping M4 core and some peripherals alive ?

Question asked by harish Ganesan on Oct 25, 2017
Latest reply on Aug 7, 2018 by Bob Jones

In our application , it is necessary to keep the M4 alive in certain situations , while shutting down the A7 core inorder to save power . Going by the details present in the Technical Reference Manual , we can configure the SoC to shutdown specific domains in the SoC .

 

But when we tried to configure such details through memtool , the memory remained unresponsive to all the writes that were performed on the General Power Controller .

 

When trying to take the i.MX7 to suspend by writing mem to /sys/power/state , The entire system was put into sleep mode including the M4 core . Is there a way in the linux user space , where we can configure the domains which need to be turned off during deep sleep mode ? Or is there any way at all , by modifying things in kernel space to acheive the selective suspend that we are desiring ? 

 

Thank You 

G.Harish

 

imx7d i.mx7d sabre suspend deep sleep gpc power managment cortex - m4 cortex-a7

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